Dental Applicator

ABSTRACT

The invention relates to a dental applicator comprising an applicator housing and a plunger body guided movably in said applicator housing, wherein the applicator housing comprises a connection for detachably mounting a cannula in a pressure-resistant manner, said cannula comprising a connection body and a cannula tube that is rigidly connected in or on said connection body, and the applicator housing (12) and/or plunger body (14) having a receiving device (22) for at least partially receiving a bendable cannula tube (20).

The invention concerns a dental applicator in accordance with thepreamble of claim 1.

It is known that for the application of fluid dental materials, dentalapplicators are used. Dental materials are often of quite high quality,and the exact metering of the dental material to be applied is thereforenecessary not only for dental-medical, but also for economic reasons.

Therefore, dental materials are often held ready in an applicatorhousing with a plunger, wherein the exact quantity of dental material tobe applied is determined with the help of auxiliary devices, such as ascale, for instance.

The dental material frequently needs to be applied in positions whichare poorly accessible, such as a root canal of a tooth, for example. Forthis purpose, a cannula is then typically used, which is provided with aconnection body and a cannula tube. The cannula tube has a very smalldiameter of, for instance, 0.8 mm, wherein the diameter, however, mayalso vary strongly compared with this.

The cannula is then separable from the applicator housing.

In order to account for the requirements of the application, theproducers of such dental applicators offer cannulas with cannula tubesof different designs. Examples for this are straight cannula tubes, butalso cannula tubes which have been bent to be curved, which are crankedor which are angled.

In some cases, the dentist now needs to apply the dental material atdifferent places inside the mouth of the patient using the same dentalmaterial. So far, he has had to change the cannula with itscorresponding cannula tube for this purpose, for instance from straightto angled. In the process, not only a certain amount of dental materialwas lost, but so far there has been the necessity of keeping ready twodifferent cannulas.

In contrast to this, the invention is based on the task of creating adental applicator in accordance with the preamble of claim 1, which isuniversally usable, i.e. makes possible an adaptation to differentapplication situations, but still makes possible savings from an overalleconomic point of view.

This task is solved, in accordance with the invention, by claim 1.Advantageous further developments result from the subordinate claims.

In accordance with the invention, it is particularly favourable that theapplicator housing and/or the plunger body itself, i.e. a part of thedental applicator, makes it possible to adapt the shape of the cannulatube to the different requirements of the application place for thefirst time.

For this purpose, the cannula tube is provided to be flexible, forinstance made out of steel with a wall thickness of 80 μm, with adiameter of 0.8 mm and a total length of 25 mm.

The bending in accordance with the invention is preferably, but notinevitably, done with the help of a bending aid which determines thebending radius. Such a steel tube may be bent without any problem arounda bending radius of less than 10 mm, for example of 5 mm.

If the end, i.e., for instance, the foremost 3 mm of the cannula tube,is inserted into the receiving device and a bending force is exerted,this will typically to first result in an elastic, and then a plasticdeformation with a bending radius which results essentially uniformlyover the course of the tube. Only when the bending radius becomessmaller than admissible, and the tube virtually cracks at some position,a necking is accomplished, and the tube can no longer be used. This,however, is prevented, in accordance with the invention, with the helpof the comparatively long cannula tube with a length of at least 10 mmand the comparatively small tube outer diameter with a thickness of 1.5mm at the most, but also in that, for example, via a stop or the like,the maximum bending is limited.

In accordance with the invention, it is possible for the dentist, withan advantageous embodiment, to adapt the bending shape achieved to theresult desired. If the bending radius is to be formed rather close tothe connection body, for instance, the dentist will push, during thebending, the applicator housing in the direction towards the receivingaperture, or slightly beyond the receiving device. If, on the otherhand, the bending radius is to be created close to the end of thecannula tube, the dentist will slightly pull back the applicator housingduring the bending, such that the desired shape will be created in eachcase.

In this fashion, it is also possible for the bending aid in accordancewith the invention to provide an essentially S-shaped course of thecannula tube if this is desired. For this purpose, a pulling force isfirst exerted during the bending, then the applicator housing is rotatedby 180°, and then a pulling force is exerted during the bending.

It is particularly favourable that the receiving device is provided witha depth stop in an advantageous embodiment in accordance with theinvention. By means of this, the leverage which is exerted during thebending may be set right from the start. If the depth stop is at a depthof 3 mm, for example, the front 3 mm of the cannula tube will enter intothe receiving device, and the length of the bending lever will then alsoamount to 3 mm, which is sufficient with a diameter of the tube of 1 mm.

It is to be understood that thicker cannula tubes may preferably also beprovided with deeper depth stops, and thinner ones with less deep depthstops. A dental applicator may also have a number of receiving devicesof different diameters, depending on the cannula applied and its tube.

Preferably, the cannula tube is inserted into the receiving device withits end with little clearance of, for instance, 20 μm or 50 μm. Thecannula tube may then be easily detached after the bending, but there isstill a secure bending guidance.

In the case that the applicator housing or the plunger housing isproduced by injection moulding, the receiving device may be directlyintegrated in it, for example by means of a corresponding blind hole.

However, it is also possible to produce a corresponding bushingseparately out of some suitable material and insert it into acorresponding recess in the applicator housing or in the plunger body.This embodiment is preferable when the same applicator housing andplunger body are to be held ready for different diameters of thecannulas, but afterwards—for instance depending on the material—adecision is to be made for one.

For this purpose, during packing, the corresponding receiving devicebushing is then packed together with the applicator housing and theplunger body suiting the cannula.

It is insofar also possible to pack and deliver the receiving devicebushing together with a suiting cannula.

Preferably, the cannula tubes in accordance with the invention arestraight in their delivered state, and may then be bent into any shapewith the help of the receiving device in accordance with the invention.

In an advantageous embodiment, the receiving device is distinctly deeperthan it would be required by the actual bending process. A straightportion is followed by a curved portion of a length of severalmillimetres. The bending is now done in such a fashion that the bendingtube leans against the curved portion at some position, and thereforethe bending radius is predetermined there. This has the advantage thatthe radius will by no means become smaller than is minimally admissible.

In an advantageous embodiment it is intended to provide the receivingdevice at any suitable position of the applicator housing and/or of theplunger body which is provided with a corresponding wall thickness. Thishas the advantage that no additional protrusion or the like needs to beprovided there. A notable weakening of the structure of the plunger bodyand/or the applicator housing is not connected with this.

In this fashion, the receiving device may, for example, be put intopractice without any problem on the back plate or grill plate of theapplicator housing essentially radially. Another possibility ofattachment is the press plate of the plunger body, wherein here there isthe possibility of radial or coaxial positioning.

A number of receiving devices with suitable diameters may also beattached at the suitable position, and it is also possible to put intopractice an angle scale in case of radial arrangement to indicate thecurvature of the cannula tube.

Further advantages, details and features result from the followingdescription of several exemplary embodiments of the invention with thehelp of the drawings which show:

FIG. 1 a schematic side view of an embodiment of a dental applicator inaccordance with the invention;

FIG. 2 the embodiment in accordance with FIG. 1, however depicting theapplicator housing with the cannula detached, viewing it fromunderneath;

FIG. 3 a schematic perspective view of a further embodiment of a dentalapplicator in accordance with the invention; and

FIG. 4 a detail of a further embodiment of a dental applicator inaccordance with the invention.

In FIG. 1, a dental applicator 10 in one embodiment is depictedschematically. The dental applicator is provided with an applicatorhousing 12 in which a plunger body 14 is guided in a basically knownfashion. The guidance may, for instance, be a sliding guide in themanner of a syringe. However, it may also be provided with a threading,such that material may be squeezed out of the applicator housing atgreat pressure by means of rotating the plunger body.

The dental applicator 10 is further provided with a cannula 16 which isdetachably attached to the front end of the applicator housing. Theattachment is done, for example, via a screw thread or, for example, abayonet lock. In a basically known fashion, the attachment is formedsuch that a sealing is accomplished, such that dental material underpressure, which is provided inside the applicator housing 14, issqueezed into the cannula 16.

The cannula 16 consists of a connection body 18 and a cannula tube 20.The connection body 18 is preferably made out of a plastic materialsuitable for this purpose, as are the applicator housing 12 and theplunger body 14. In contrast, the cannula tube 20 is flexible inaccordance with the invention. The cannula tube 20 is insofarplastically deformable with corresponding bending forces, but mayadditionally also be elastically deformable to a lower extent.

It is preferably rather thin-walled with a wall thickness of, forexample, between 50 μm and 200 μm, and a diameter of, for example, 1 mm.Its length may amount to between 1 cm and, for instance, 3 cm. It may bemade out of steel or any other suitable material which, in any case, isresistant to the dental material to be applied.

In accordance with the invention, the dental applicator is provided witha receiving device 22 in the area of the applicator housing/plungerbody. In the embodiment depicted, two receiving devices 22 are depictedslightly schematically. They extend in the manner of blind holesparallel to a handle plate 24 of the applicator housing. The handleplate 24 serves for the purpose of closing the applicator housingtowards the back and is also a gripping device at the same time. It istypically gripped from behind with two fingers, for example with indexfinger and middle finger, while pressure is exerted onto a press plate26, which closes the plunger body 14 towards the back, by the thumb.

The receiving devices 22 extend in a radial direction in the form ofblind holes. They are formed on an annular reinforcement 28 which leansagainst the handle plate 24 in the direction towards the cannula 16 andalso serves as a gripping device. The diameter of one receiving deviceamounts to 1.25 mm and is insofar determined for the receiving ofcannula tubes with a diameter of 1.2 mm. In contrast to this, thediameter of the other receiving device amounts to 1.05 mm and isdetermined for the receiving of cannula tubes with a diameter of 1.0 mmThe depth of the receiving device concerned, which is formed in themanner of a blind hole, amounts to 3.5 mm or 3 mm, respectively.

This exemplary embodiment allows a slim configuration of the dentalapplicator in accordance with the invention. In order to accomplish thebending process, the cannula tube 20 is detached and is inserted intothe suiting receiving device 22 and may then be bent as desired.

After the bending process, the cannula 16, with the cannula tube 20 nowcurved, is again attached, together with the connection body 18, to theapplicator housing 12.

From FIG. 2 it can be taken that the handle plate 24 may bear markingswhich numerically support the bending process. For this purpose, themarkings 0°, 30° and 45°, corresponding to one bending around eachrespective angle named, are entered. The user may thus see, wheninserting into the receiving device 22 of the applicator housing 12 orthe annular reinforcement 28, respectively, around what angle he is justdoing the bending.

In another embodiment which is not depicted here, stops are providedwhich make it possible to limit the bending process and at the same timesuggest to the user from what bending angle on a necking of the cannulatube 20 would have to be feared.

The invention is not limited to the arrangement of the receiving device22 on the applicator housing 12. The receiving device may be attached atany suitable position, also somewhere on the wall or the front side ofthe applicator housing 12.

In accordance with FIG. 3, it is attached centrally inside the plungerbody 14 within the press plate 26. Here as well it holds true that whenthe connection body 18 is removed from the applicator housing 12 and thecannula tube 20 is inserted into the receiving device 22 with its fronttip, bending is possible. In accordance with FIG. 3, the cannula tube 20is already provided with a bent tip.

From FIG. 4, the embodiment of a receiving device 22 is visible indetail. Here, the receiving device 22 is provided in the form of abushing 40, wherein it is to be understood that a corresponding shape isalso possible with an integrated, i.e. a one-piece, implementation.

The end 42 of the receiving device 22 which points towards the outsideis provided with a radius which at the same time forms a bending stop.The cannula tube 20 may thus be bent along the curved end 42 with apredetermined bending radius. The curved end surface 42 has the shape ofa circular ring, such that it may be bent into any direction. Anembodiment of the bending end with predetermined ramp angles (43) isalso imaginable.

As can be seen from FIG. 4, the receiving device 22 forms at the sametime a depth stop 44. The cannula tube 20 may be inserted down to thebottom of the receiving device, which is until the tip of the cannulatube 20 abuts against the bottom of the receiving device inside thereceiving device.

In this position, the cannula tube 20 or, to be more precise, its frontend, may be bent in any suitable fashion.

In the exemplary embodiment depicted in accordance with FIG. 4, thebushing 40 is exchangeable, such that also bushings with receivingdevices 22 with any different suitable inside diameter may be insertedinstead of the former.

1. Dental applicator comprising an applicator housing and a plunger bodyguided movably in said applicator housing, wherein the applicatorhousing comprises a connection for detachably mounting a cannula in apressure-resistant manner, said cannula comprising a connection body anda cannula tube that is rigidly connected in or on said connection body,wherein the applicator housing (12) and/or plunger body (14) has areceiving device (22) for at least partially receiving a bendablecannula tube (20).
 2. Dental applicator in accordance with claim 1,where the receiving device (22) is a recess on the applicator housing(12) and/or the plunger body (14) into which the cannula tube (20) maybe partially inserted.
 3. Dental applicator in accordance with claim 1,where the receiving device (22) is provided with a depth stop (44) andwherein the cannula tube (20) may be inserted into the receiving device(22) until it abuts against the depth stop (44).
 4. Dental applicator inaccordance with claim 1, where a recess of the receiving device (22) hasa depth which amounts to at least twice the diameter of the cannula tube(20).
 5. Dental applicator in accordance with claim 5, where the cannulatube (20) is provided with a diameter having a clearance of at least 50μm inside the recess, and wherein the recess is provided with an insidediameter which is at least 50 μm larger than the outside diameter of thecannula tube (20).
 6. Dental applicator in accordance with claim 1,where the receiving device (22) is provided with at least two bendingstops which are spaced apart from each other which bending stops areoffset towards each other by 180°.
 7. Dental applicator in accordancewith claim 1, where the receiving device (22) is provided with a recess,is circular, and has a straight course.
 8. Dental applicator inaccordance with claim 1, where the receiving device (22) is provided, onits outward-pointing end, with at least one curved end surface (42)which extends in a circularly curved fashion around the outward-pointingend (42).
 9. Dental applicator in accordance with claim 8, where thecurved end surface (42) is provided with a radius which corresponds toat least the minimally admissible bending radius of the cannula tube(20).
 10. Dental applicator in accordance with claim 8, where the curvedend surface (42) may be provided, on the levelling-off margin of theradius, with at least one pre-defined ramp angle (43).
 11. Dentalapplicator in accordance with claim 1, where the receiving device (22)enters into the plunger body (14) in a fashion coaxially with theplunger body.
 12. Dental applicator in accordance with claim 11, wherethe receiving device (22) is formed as a recess on the plunger body(14), which recess extends radially.
 13. Dental applicator in accordancewith claim 1, where the receiving device (22) is formed on theapplicator housing (12), radially or in parallel to the housingits-axis, on the bottom of the applicator housing (12), or on theconnection for the connection body (18) of the cannula (16).
 14. Dentalapplicator in accordance with claim 1, where the receiving device (22)is provided with a recess which extends radially away from a shank ofthe plunger body (14) or from the applicator housing (12), adjacently tothe respectively associated handle plate (24), and wherein the handleplate (24) which is adjacent to the recess, angle markings are attachedwhich signal the bending angle of the cannula tube (20) during thebending of the end of the cannula tube (20) which is inserted into thereceiving device (22).
 15. Dental applicator in accordance with claim 1,wherein a recess of the receiving device (22) has a depth which amountsto at least three times the diameter of the cannula tube (20). 16.Dental applicator in accordance with claim 1, wherein a recess of thereceiving device (22) has a depth which amounts to no more than tentimes the diameter of the cannula tube (20).
 17. Dental applicator inaccordance with claim 1, wherein the receiving device (22) enters intothe plunger body (14) in a fashion coaxially with the plunger body on ahandle plate (24) of the plunger body (14).
 18. Dental applicator inaccordance with claim 17, wherein the receiving device (22) is formed asa recess on the plunger body (14), which recess extends radially on aplunger shank or the handle plate (24) of the plunger body (14). 19.Dental applicator in accordance with claim 1, wherein the receivingdevice (22) is formed on a handle plate (24) of the applicator housing(12) radially or in parallel to the housing axis.